One thing I do remember seeing them in, though not a movie per se, was a Hallmark Hall of Fame TV production of the classic play, The Magnificent Yankee, about Supreme Court justice Oliver Wendell Holmes, which aired in 1965. My recollection, even watching it as a kid, was that it was a total joy. Years later, when I went to UCLA for graduate school, I discovered that the school had the greatest collection of Hallmark Hall of Fame specials anywhere, everything in fact -- though it was only available for academic purposes. Being a student, I thought that that might qualify, and it did. For some reason, I only took advantage to see two of their classic productions. One was A Storm in Summer, for which Peter Ustinov won the Emmy Award, written by Rod Serling -- and it was as great as I remembered, though I knew it would be since it hadn't aired that much earlier. The other I wanted to see was The Magnificent Yankee, curious how it lived up to my memory all that time before when I was much younger. And...it was just as superb. I wish both of these were available to the public. Why one of the several Hallmark Channels doesn't air their collection -- even in the middle of the night, where they could be recorded for later viewing -- is beyond me.
Alas, no, I don't have footage of The Magnificent Yankee. I mention it only for the sake of perspective. I should note that many people have seen the work of Lynn Fontanne, though, but don't know it. And I say "seen the work" specifically, because they haven't seen her in it. She did the narration of the original, legendary TV production of Peter Pan with Mary Martin.
As I said, there isn't much footage of the two of them acting, though you can get their one, famous film, The Guardsman -- recreating their roles from the major Broadway hit -- which is available on Netflix. It's old and dated, from 1931, but it's still enjoyable and especially a treat to see them both. It's the story of an actor husband who suspects his wife of infidelity, and so pretends to be a foreign nobleman to try to strike up an affair with her and prove himself right.
And at least we have a trailer for that.
All of this is a long way to lead into this video. It's from 1970, when The Lunts were given a special Tony Award. It's introduced by Julie Andrews, and then presented by another then-married couple, Maggie Smith and Robert Stephens.